The number of people forced to flee their homes in two regions of Burkina Faso besieged by ethnic and jihadist violence increased more than six-fold since January to around 500 000, the United Nations and aid groups said.
Attacks by Islamist militants and clashes between herding and farming communities surged this year, killing hundreds of civilians and soldiers.
Once a pocket of relative calm in the Sahel, Burkina suffered a home-grown insurgency for three years, amplified by a spill-over of jihadist violence from Mali.
In a statement at the end of a visit to Burkina, 11 UN aid agencies and non-governmental organisations, said the insecurity crippled the health and education sectors.
“The mission was taken aback by the severity and urgency of the humanitarian crisis,” said Margot van der Velden, director of emergencies for the UN World Food Programme.
The agencies called on donors to step up assistance to Burkina, which needs $187 million to assist 1,3 million people.
In the most recent large-scale violence, suspected jihadists killed around 20 people in an attack on a gold-mining site in the north last week.